X-ray and synchrotron investigations of heterogeneous systems based on multiwalled carbon nanotubes

This paper presents the results of a complex investigation of heterogeneous systems based on multiwalled carbon nanotubes with the outer surfaces covered by iron oxide (Fe$_3$O$_4$) nanocoatings deposited using iron pentacarbonyl as a precursor. Investigations were performed by the methods of electron microscopy, X-ray diffractometry, and ultrasoft X-ray spectroscopy with synchrotron radiation. It was established that the formed thin coatings are continuous and nonuniform in thickness. It was shown that good adhesion of iron oxide on the multiwalled carbon nanotube surface is provided by the formation of epoxy and double carbon-oxygen bonds; in this case, the outer graphene layer of nanotubes is not destroyed and retains the hexagonal structure.